Proof of Authority (PoA)

Kaly proof of authority consensus protocols comparison

Kaly implements the QBFT, proof of authority (PoA) consensus protocols. PoA consensus protocols work when participants know each other and there is a level of trust between them.

PoA consensus protocols have faster block times and a much greater transaction throughput than the Ethash proof of work consensus protocol used on the Ethereum Mainnet.

In QBFT, a group of nodes in the network act as validators. The existing nodes in the signer/validator pool vote to add nodes to or remove nodes from the pool.

Properties

• Immediate finality.

• Minimum number of validators.

• Liveness.

• Speed.

Immediate finality

QBFT has immediate finality; there are no forks and all valid blocks get included in the main chain.

Minimum number of validators

To be Byzantine fault tolerant, QBFT requires a minimum of four validators.

Liveness

QBFT networks require greater than or equal to two-thirds of validators to be operating to create blocks. For example, a QBFT of:

• Four to five validators tolerates one unresponsive validator.

• Six to eight validators tolerates two unresponsive validators.

Networks with three or less validators can produce blocks but do not guarantee finality when operating in adversarial environments.

Speed

For QBFT , the time to add new blocks increases as the number of validators increases.